A virus that may encourage the body to grow more fat cells could, paradoxically, lower diabetes risk. Nikhil Dhurandhar at the Pennington Biomedical Research Center in Baton Rouge, Louisiana, and colleagues examined the long-term effects of a common virus – adenovirus-36 (Ad-36) – on humans. The team analysed blood samples made available from 1400 volunteers in a decades-long epidemiological study. The researchers detected antibodies to Ad-36 in 14.5 per cent of the subjects when they first joined the study – a prevalence in line with studies on the US adult population.